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Inferior glenohumeral ligament anterior band

The anterior band of the inferior glenohumeral ligament (IGHL) is a key static stabilizer of the anteroinferior aspect of the glenohumeral joint. It forms the anterior component of the inferior glenohumeral ligament complex, which includes the anterior band, posterior band, and the axillary pouch connecting them.

This ligament plays a critical role in preventing anterior dislocation of the humeral head, especially when the arm is in abduction and external rotation. It is the thickest and most functionally important portion of the IGHL complex, serving as the primary restraint against anterior translation of the humeral head.

Synonyms

  • Anterior band of IGHL

  • Anterior inferior glenohumeral ligament

  • Anterior limb of the inferior glenohumeral complex

Location and Structure

  • The IGHL complex extends from the inferior glenoid labrum and glenoid rim to the anatomic neck of the humerus.

  • The anterior band arises from the anteroinferior glenoid margin and fibrous capsule, running obliquely downward and laterally to insert onto the inferior aspect of the humeral neck.

  • Together with the posterior band and axillary pouch, it forms a hammock-like structure supporting the humeral head inferiorly.

Attachments

  • Origin: Anteroinferior glenoid rim and adjacent glenoid labrum (typically between the 3 and 5 o’clock position in the right shoulder).

  • Insertion: Inferior aspect of the anatomical neck of the humerus, blending with the joint capsule.

  • Capsular continuity: Merges with anterior capsule and fibers of the middle glenohumeral ligament superiorly.

Relations

  • Anteriorly: Subscapularis muscle and tendon, joint capsule, and subcoracoid bursa.

  • Posteriorly: Axillary pouch of the IGHL complex.

  • Superiorly: Middle glenohumeral ligament and anterior glenoid labrum.

  • Inferiorly: Axillary recess of the glenohumeral joint.

  • Medially: Inferior glenoid rim and labrum.

  • Laterally: Inferior aspect of the humeral head and neck.

Nerve Supply

  • Articular branches from the axillary nerve and suprascapular nerve provide proprioceptive and nociceptive fibers to the capsuloligamentous complex.

Function

  • Anterior stabilization: Major restraint to anterior translation when the shoulder is in 90° abduction and external rotation.

  • Inferior support: Works with posterior band to prevent inferior displacement of the humeral head.

  • Joint congruency: Maintains humeral head position within the glenoid fossa during motion.

  • Dynamic integration: Acts synergistically with rotator cuff muscles and capsule for glenohumeral stability.

  • Prevents anterior dislocation: Particularly vulnerable in throwing athletes and traumatic shoulder injuries.

Clinical Significance

  • Bankart lesion: Avulsion of the anteroinferior labrum–IGHL complex from the glenoid rim following anterior dislocation.

  • HAGL lesion (Humeral Avulsion of the Glenohumeral Ligament): Detachment of the IGHL from the humeral neck, often associated with shoulder instability.

  • Perthes lesion: Partial detachment of IGHL with intact periosteum.

  • Anterior shoulder instability: IGHL anterior band insufficiency or tears are key structural causes.

  • Capsulolabral reconstruction: Restoration of the anterior band is vital in arthroscopic stabilization procedures.

  • Imaging importance: MRI and MR arthrography are gold standards for detecting IGHL tears, detachments, and scarring.

MRI Appearance

  • T1-weighted images:

    • Normal ligament: Low signal (dark band) extending from glenoid rim to humeral neck.

    • Marrow: Bright signal within humeral neck and glenoid due to fatty content.

    • Capsule: Intermediate-to-low signal blending with ligament fibers.

    • Pathology: Avulsion or tear appears as focal discontinuity or fluid-intense gap at humeral or glenoid attachment.

  • T2-weighted images:

    • Normal IGHL anterior band: Uniform low signal, slightly darker than muscle.

    • Tear or avulsion: Bright hyperintense fluid signal replacing ligament continuity.

    • Capsular thickening: Appears intermediate-to-bright, with adjacent joint effusion hyperintense.

    • Post-traumatic edema: Bright signal in surrounding soft tissue or marrow.

  • STIR:

    • Normal ligament: Dark  signal.

    • Pathologic ligament: Bright hyperintensity indicating edema, inflammation, or partial tear.

    • Useful for: Early detection of ligament sprains and adjacent marrow edema.

  • Proton Density Fat-Saturated (PD FS):

    • Normal ligament: Low, uniform signal outlining the anteroinferior capsule.

    • Tear or detachment: Bright hyperintense region at humeral or glenoid insertion.

    • Pericapsular inflammation: Diffuse high signal adjacent to ligament.

    • Excellent for evaluating HAGL, Bankart, or capsular redundancy.

  • T1 Fat-Sat Post-Contrast:

    • Normal ligament: Minimal enhancement.

    • Acute inflammation or capsulitis: Focal or linear enhancement along ligament.

    • Chronic tear or scar: Irregular, thickened enhancement pattern around ligament and capsule.

CT Appearance

Non-Contrast CT:

  • Ligament itself: Not directly visualized due to soft-tissue density.

  • Indirect signs: Subtle soft-tissue thickening or joint effusion in anteroinferior recess.

  • Associated findings:

    • Bony Bankart lesion (avulsion of anterior glenoid rim).

    • Humeral head impaction fracture (Hill-Sachs lesion).

    • Glenoid irregularity or calcification near attachment.

Post-Contrast CT (standard or CT arthrography):

  • Contrast delineates joint capsule and ligament contour.

  • IGHL tear: Contrast extravasation at humeral neck (HAGL) or along anteroinferior glenoid (Bankart).

  • Capsular redundancy: Visualized as contrast pooling in inferior recess.

  • Ideal for patients unable to undergo MRI or for detailed bony evaluation in instability.

MRI image

Inferior Glenohumeral Ligament Anterior Band axial cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000